1. Field of the Invention
The present invention relates to an expansion device connected to a compact electronic apparatus capable of being battery-driven, such as a lap-top type personal computer, a word processor, or the like, thereby expanding the functions of the electronic apparatus.
2. Description of the Related Art
One of conventionally known portable personal computers comprises a substantially rectangular-box like housing. A keyboard is situated at the front part of the housing, and a flat-panel type display is rotatably mounted on the rear of the keyboard.
In this type of personal computer, in order to enhance the portability, a rechargeable battery pack is removably attached to the housing and is used as a driving power source.
Recently, there is a demand that a memory, a printer or a hard-disc drive unit be connected to this portable personal computer, where necessary, thereby expanding the computer functions of the portable personal computer up to the level of a desk-top type computer.
The above type of portable personal computer, however, has a thin, compact housing for achieving high portability. It is, therefore, practically impossible to keep the space within the housing for installation of an expansion device.
Under the situation, an expansion device, such as a hard-disc drive unit, for example, is installed outside the computer housing and is connected to the computer through a connector exposed on the rear face of the housing. In this case, a power source for driving the expansion device must be provided separately.
Accordingly, in order to expand the functions of the computer, a power source used exclusively for the expansion device must be provided, along with the expansion device itself. Thus, the computer, if associated with the expansion device and power source therefor, becomes very large in size and heavy. This deteriorates the portability of the computer.